gzuncompress - PHP code example

The PHP Function Gzuncompress

PHP has many built-in functions but also allows you to create your own. Functions are blocks of code that can be called from within a script to perform a specific task. Functions do not execute automatically when a page loads, but need to be called by the script using a call to function syntax.

This function takes a string of data compressed by gzcompress() and decodes it into its original uncompressed form. The return value is the orignial uncompressed data or false on error.

The first ten bytes of the output are the standard gzip file header. The last four bytes contain a checksum of the encoded body.

If a level is specified it must be between 0 and 9. If not, the default compression of the zlib library will be used.

Note: gzuncompress does NOT append a CRC32 checksum to the output, unlike gzdeflate which does. This is a bug in PHP, not a problem with gzip.

The gzuncompress function does not support the "Force_GZIP" encoding option. Use gzencode() instead if you need to send a gzip header.

You can enable strict typing for functions by adding a type declaration before the function name, right after the opening curly () bracket. If you do this, PHP will not let you pass a variable that does not match the function's declared type. This is useful when writing reusable code that needs to be compatible across versions of PHP.

gzuncompress example

if ($decoded !== false) {
                return $decoded;
            }
        }

        $decoded = self::compatible_gzinflate($data);
        if ($decoded !== false) {
            return $decoded;
        }

        if (function_exists('gzuncompress')) {
            $decoded = @gzuncompress($data);
            if ($decoded !== false) {
                return $decoded;
            }
        }

        return $data;
    }

    /** * Decompression of deflated string while staying compatible with the majority of servers. * * Certain Servers will return deflated data with headers which PHP's gzinflate() * function cannot handle out of the box. The following function has been created from * various snippets on the gzinflate() PHP documentation. * * Warning: Magic numbers within. Due to the potential different formats that the compressed * data may be returned in, some "magic offsets" are needed to ensure proper decompression * takes place. For a simple progmatic way to determine the magic offset in use, see: * https://core.trac.wordpress.org/ticket/18273 * * @since 1.6.0 * @link https://core.trac.wordpress.org/ticket/18273 * @link https://www.php.net/gzinflate#70875 * @link https://www.php.net/gzinflate#77336 * * @param string $gz_data String to decompress. * @return string|bool False on failure. * * @throws \WpOrg\Requests\Exception\InvalidArgument When the passed argument is not a string. */

$parsedFrame['data_length_indicator'] = getid3_lib::BigEndian2Int(substr($parsedFrame['data'], 0, 4), 1);
                    $parsedFrame['data']                  =                           substr($parsedFrame['data'], 4);
                }
            }

            // Frame-level de-compression             if ($parsedFrame['flags']['compression']) {
                $parsedFrame['decompressed_size'] = getid3_lib::BigEndian2Int(substr($parsedFrame['data'], 0, 4));
                if (!function_exists('gzuncompress')) {
                    $this->warning('gzuncompress() support required to decompress ID3v2 frame "'.$parsedFrame['frame_name'].'"');
                } else {
                    if ($decompresseddata = @gzuncompress(substr($parsedFrame['data'], 4))) {
                    //if ($decompresseddata = @gzuncompress($parsedFrame['data'])) {                         $parsedFrame['data'] = $decompresseddata;
                        unset($decompresseddata);
                    } else {
                        $this->warning('gzuncompress() failed on compressed contents of ID3v2 frame "'.$parsedFrame['frame_name'].'"');
                    }
                }
            }
        }

        if (!empty($parsedFrame['flags']['DataLengthIndicator'])) {

                case '@PRQ': // adobe PRemiere Quicktime version                     $atom_structure['data'] = $atom_data;
                    break;

                case 'cmvd': // Compressed MooV Data atom                     // Code by ubergeekØubergeek*tv based on information from                     // http://developer.apple.com/quicktime/icefloe/dispatch012.html                     $atom_structure['unCompressedSize'] = getid3_lib::BigEndian2Int(substr($atom_data, 0, 4));

                    $CompressedFileData = substr($atom_data, 4);
                    if ($UncompressedHeader = @gzuncompress($CompressedFileData)) {
                        $atom_structure['subatoms'] = $this->QuicktimeParseContainerAtom($UncompressedHeader, 0, $atomHierarchy, $ParseAllPossibleAtoms);
                    } else {
                        $this->warning('Error decompressing compressed MOV atom at offset '.$atom_structure['offset']);
                    }
                    break;

                case 'dcom': // Data COMpression atom                     $atom_structure['compression_id']   = $atom_data;
                    $atom_structure['compression_text'] = $this->QuicktimeDCOMLookup($atom_data);
                    break;

else
                                        {
                                            $this->body = trim($decoder->data);
                                        }
                                        break;

                                    case 'deflate':
                                        if (($decompressed = gzinflate($this->body)) !== false)
                                        {
                                            $this->body = $decompressed;
                                        }
                                        else if (($decompressed = gzuncompress($this->body)) !== false)
                                        {
                                            $this->body = $decompressed;
                                        }
                                        else if (function_exists('gzdecode') && ($decompressed = gzdecode($this->body)) !== false)
                                        {
                                            $this->body = $decompressed;
                                        }
                                        else
                                        {
                                            $this->error = 'Unable to decode HTTP "deflate" stream';
                                            $this->success = false;
                                        }

  public static function uncompressQueryParameter(string $compressed): string|bool {
    // Because this comes from user data, suppress the PHP warning that     // gzcompress() throws if the base64-encoded string is invalid.     return @gzuncompress(base64_decode(str_replace(['-', '_'], ['+', '/'], $compressed)));
  }

  /** * Filters a URL query parameter array to remove unwanted elements. * * @param array $query * An array to be processed. * @param array $exclude * (optional) A list of $query array keys to remove. Use "parent[child]" to * exclude nested items. * @param string $parent * Internal use only. Used to build the $query array key for nested items. * * @return array * An array containing query parameters. */

    public static function uncompress($value)
    {
        if (!\is_string($value)) {
            return $value;
        }

        if (!self::$compress) {
            return \unserialize($value);
        }

        $uncompressed = gzuncompress($value);
        if ($uncompressed === false) {
            throw new \RuntimeException(sprintf('Could not uncompress "%s"', $value));
        }

        return unserialize($uncompressed);
    }
}

$decompressed = @gzinflate( $compressed );
        if ( false !== $decompressed ) {
            return $decompressed;
        }

        $decompressed = self::compatible_gzinflate( $compressed );
        if ( false !== $decompressed ) {
            return $decompressed;
        }

        $decompressed = @gzuncompress( $compressed );
        if ( false !== $decompressed ) {
            return $decompressed;
        }

        if ( function_exists( 'gzdecode' ) ) {
            $decompressed = @gzdecode( $compressed );

            if ( false !== $decompressed ) {
                return $decompressed;
            }
        }

        $zlibHeader = unpack('n', substr($body, 0, 2));
        if ($zlibHeader[1] % 31 == 0 && ord($body[0]) == 0x78 && in_array(ord($body[1]), array(0x01, 0x5e, 0x9c, 0xda))) {
            return gzuncompress($body);
        } else {
            return gzinflate($body);
        }
    }

    /** * Create a new Zend_Http_Response object from a string * * @param string $response_str * @return Zend_Http_Response */